Good Spot Meter to go with M8?

[DaveEP]

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Once you get through the calibration procedure, you will understand completely what your camera can and cannot capture. Knowing those limits allows you to work within the boundaries (rather than hoping you did not exceed them) is a liberating feeling.

Nick

 

Thanks for your input in to this thread Nick. There will always be people who agree, and people who disagree on any/all subjects, and I have learned to pick and choose who I listen to on any given subject.

 

I think your sugestion above makes good sense. I am thinking about this light meter myself, but have not yet made the decision to purchase. My 358 has done sterling work, but alas does not include spot. I wish I had spent the extra money the first time around. How many times have I done this - and still I don't learn!!

[nzav]

The Jpeg enbedded in the DNG is quite small, nowhere near full-sized. By itself it wouldn't support zooming down to pixel level, which is what I believe the camera allows. So I think there may be some rendering of the RAW file at some point.

 

Of course there is... a JPEG is a rendering of a RAW file! That is my point Steve, you can't make any assessment from a RAW file until it is converted into a JPEG or TIFF. By its nature, it is raw data in digital form.

 

Understanding that, let's go to the next step; you are looking at a JPEG conversion on the camera's LCD that was made by a tiny limited set of processing instructions inside your camera's rather tiny CPU, and you have no idea what those instructions did to the image data to make it viewable.

 

On the other hand, when you convert the RAW file (which has not even decoded the color info yet) with a sophisticated set of software algorithms in a computer with a decent CPU, adequate RAM, and actually have the power to adjust the gamma (curves and or levels), ISO, color balance, etc., which image will be closest to the picture you saw as you pressed the shutter?

 

Now let's add one more fact no one seems to mention; every change made in converting a RAW file into a viewable image discards some file data. Don't panic, the original RAW data is left intact; only the conversion has had bits thrown out. The JPEG on your LCD has already discarded enough data to make your head spin, and you had no choice in what was trashed. That scaled-down algorithm inside the camera decided what was important enough to keep and show you!

 

Do some experimenting like I described earlier in this thread and compare the same image on your camera's LCD with the converted RAW file on your computer's display. You will be amazed by how much information is missing on the camera's LCD. Also compare both at 100% (camera LCD image zoomed to 1:1) and you should see more detail on your computer's display than on the camera's LCD. I am not talking about physical size but visible detail.

 

To illustrate my point, we used Polaroid film to make test shots of our subjects in the studio before shooting real film. Those Polaroids served a purpose to assess composition and effects of lighting but were never considered an exposure tool. We knew the speed (ISO), color, and tonal range were not going to be the same as the Ektachrome film, but with experience were able to visually "translate" between the two media.

 

In more ways than not, the JPEG on a camera's LCD is the digital equivalent of a Polaroid, and just like the Polaroid, it usually blows highlights way before the RAW capture. If you shoot RAW files, then it is only an approximation of what you potentially captured. Bottom line - only knowing the exact DR of your film/sensor will allow you to extract the maximum quality from any shot. Polaroids and JPEGs will not give you that information.

 

I apologize to any forum members forcing themselves to read through the long responses, but the questions posed here have no quick answers...

 

Nick

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[Philinflash]

...

 

Understanding that, let's go to the next step; you are looking at a JPEG conversion on the camera's LCD that was made by a tiny limited set of processing instructions inside your camera's rather tiny CPU, and you have no idea what those instructions did to the image data to make it viewable.

 

...

 

Nick

 

Agree entirely. If you are going to worry about the reflected light values from shadows and/or highlights as you certainly should whether or not you "believe" in the Zone System, you cannot seriously use the toy screen on the back of the camera, M8 or any other camera or with or without graphic representations, to make critical exposure judgments. If you cannot risk waiting to deal with it in post, you must use a decent spot meter.

 

And there probably aren't any "bad" spot meters from reputable makers on the market.

[nzav]

Agree entirely. If you are going to worry about the reflected light values from shadows and/or highlights as you certainly should whether or not you "believe" in the Zone System, you cannot seriously use the toy screen on the back of the camera, M8 or any other camera or with or without graphic representations, to make critical exposure judgments. If you cannot risk waiting to deal with it in post, you must use a decent spot meter.

 

And there probably aren't any "bad" spot meters from reputable makers on the market.

 

Actually Philip, there are... Some years ago I tested a number of professional spotmeters with film from everyone who made them at the time. All were the high-end units from the top makers. The tests involved shooting a series of exposures metered through color filters (4x4" gels) involving RGB primary (color separation filters) and a number of commonly used Wratten filters. The shots were processed and evaluated with a densitometer and the results were an eye-opener.

 

To my surprise, the worst color response (accuracy) came from the most expensive spot meter of the lot; it was well over $700 USD at the time. I called the manufacturer and they immediately sent another sample, then another, then again for a total of four versions of the same spot meter. The four identical meters varied by over four stops in their response through the same color filters! The point of this testing was not to show how the meters respond reading through color filters, but rather how they respond to actual colors; i.e. their color bias.

 

Needless to say, in this case you did not get what you paid for. I will not mention the manufacturer's name here, but the most accurate spot meters at the time were from Minolta and Sekonic. Unfortunately, Minolta no longer exists, although there is a company that seems to be making copies of Minolta meters.

 

Since these tests, R&D has improved the products, and Sekonic has been the most active in R&D with their meter lines. Perhaps the meter with the worst test score has improved, but I would not assume from my experience that they are all the same.

 

Because I shoot a lot with flash, the L-578's ability to read lower into shadows with flash than any other reflective meter is a big reson for me to use it. And when you add in the built-in PocketWizard...

 

Nick

[DavidStone]

Agree entirely. If you are going to worry about the reflected light values from shadows and/or highlights as you certainly should whether or not you "believe" in the Zone System, you cannot seriously use the toy screen on the back of the camera, M8 or any other camera or with or without graphic representations, to make critical exposure judgments. If you cannot risk waiting to deal with it in post, you must use a decent spot meter.

 

And there probably aren't any "bad" spot meters from reputable makers on the market.

I've been following this with some interest. In one of my 'previous lives' as a professional photographer in the 1960s and 70s, I studied and used the zone system to calibrate all my cameras, lenses, meters, etc., and the sense of control and predictability was extremely valuable. Since I was also shooting on sheet film, Adams' techniques were directly relevant. And of course I used a spot meter (and other types too) - an SEI photometer, very accurate, multiscale, which I still have.

 

But now I'm in the process of joining the digital world and Philip's comment about the 'toy screen' fits perfectly with my experience. Coming directly from decades of Leica use, I tend to treat the M8 just like an M6. I find the screen useful for selecting menu items, but when it comes to exposure, I'm going to do some accurate readings with my old meters and find out just what the sensor - and my lenses - are capable of, and relate this to the camera's internal meter. I see no reason not to apply the basic principles of the zone system to digital capture - but it would need to be carried through to the print, of course, which remains my final destination.

 

I know that I'm not alone in being impressed with the capabilities of this camera, and I'm determined to get the best from it.

 

David

[Philinflash]

Actually Philip, there are... Some years ago I tested a number of professional spotmeters with film from everyone who made them at the time. All were the high-end units from the top makers.

...

 

Since these tests, R&D has improved the products, and Sekonic has been the most active in R&D with their meter lines. Perhaps the meter with the worst test score has improved, but I would not assume from my experience that they are all the same.

 

Because I shoot a lot with flash, the L-578's ability to read lower into shadows with flash than any other reflective meter is a big reson for me to use it. And when you add in the built-in PocketWizard...

 

Nick

 

I stand corrected and edified by your observations. Obviously, your personal experience has revealed product weaknesses that I have not seen much discussed in journalistic reviews. I guess I have been blythely and happily using my Sekonic with great satisfaction and assumed its competitors were more or less the same.

 

I am very impressed with the M8 and it is a wonderful camera to access the digital photography technology. But that is not to say that all the old precepts of photography are "covered" with this one handy device. Some of the true basics of classical photography are still with us and have not gone away simply because there is no film in the camera. I guess that's why I like the M8. But it is important not to be seduced by all of the technology.

 

Philip Kozloff

[stunsworth]

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Nick, I wouldn't dream of using the LCD for critical viewing. Seeing if I've got the shot framed, and more importantly looking at the histogram are it's main uses - and even then unless something is way out of focus I'll wait until I can see the image on a computer screen before I decide whether to delete it or not.

[nzav]

Nick, I wouldn't dream of using the LCD for critical viewing. Seeing if I've got the shot framed, and more importantly looking at the histogram are it's main uses - and even then unless something is way out of focus I'll wait until I can see the image on a computer screen before I decide whether to delete it or not.

 

That's fine Steve, as long as you bear in mind that the histogram in your preview is derived from a JPEG conversion. Like the red clipping warnings in the preview, the preview histogram will only give you a true representation of a JPEG conversion and not your DNG file.

 

Basically what I am saying is the info displayed in that preview about your captured file is perfectly valid only if you are setup to shoot JPEG image files exclusively. The suggestions I made in this thread comparing the same captured file on the camera's LCD with it opened in ACR with corrections applied will make this very obvious.

 

The point of all this discussion is learning how much more detail is still available in your DNG file beyond the point where the preview says you've blown it! Only then will you be able to extract the maximum image quality; otherwise, following the recommendations of the camera's LCD will cause you to throw away some of the most important data bits in your capture.

 

Nick

[stunsworth]

Yeah, I realise all that Nick, the LCD is just an indication. But if it _all_ flashes red then there's a good posibility that the RAW will not be recoverable <grin>

[nzav]

I've been following this with some interest. In one of my 'previous lives' as a professional photographer in the 1960s and 70s, I studied and used the zone system to calibrate all my cameras, lenses, meters, etc., and the sense of control and predictability was extremely valuable. Since I was also shooting on sheet film, Adams' techniques were directly relevant. And of course I used a spot meter (and other types too) - an SEI photometer, very accurate, multiscale, which I still have.

 

But now I'm in the process of joining the digital world and Philip's comment about the 'toy screen' fits perfectly with my experience. Coming directly from decades of Leica use, I tend to treat the M8 just like an M6. I find the screen useful for selecting menu items, but when it comes to exposure, I'm going to do some accurate readings with my old meters and find out just what the sensor - and my lenses - are capable of, and relate this to the camera's internal meter. I see no reason not to apply the basic principles of the zone system to digital capture - but it would need to be carried through to the print, of course, which remains my final destination.

 

I know that I'm not alone in being impressed with the capabilities of this camera, and I'm determined to get the best from it.

 

David

 

David,

 

Where do you still find the lightbulbs for the SEI???

 

I completely agree the Zone System concept needs to be carried out to the final output stage, but if I got into that subject, can you imagine the length of my responses? What I am trying to get some recalcitrant forum members to accept is that the LCD on their camera does not do justice to the actual RAW file it can produce.

 

The RAW file is nothing but a stage in creating out final print. Along the way, there are different RAW converters with their own way of expanding that digital info into a printable TIFF file and even these converters will change with every new upgrade. I have most of the pro-level RAW conversion software and have seen differences in how they extract the image from the RAW file. The calibration of the L-758 incorporates the RAW converter as an integral part of the process. Of course, you don't have to plot those tedious H&D curves that Ansel was so fond of!

 

It's not all about highlight detail either. A simple example would be if RAW converter "A" gives clean shadows 5.5 stops down from your 18% gray reading exposure (Zone V), and Converter "B" starts giving unacceptable noise at 4 stops below Zone V, you have just sacrificed a stop and a half of useable DR! So if you try newer and better converters, you would certainly want to adjust you metering calibration to account for it. There are many more variables, but then this will turn into another long, long post.

 

Nick

[nzav]

Yeah, I realise all that Nick, the LCD is just an indication. But if it _all_ flashes red then there's a good posibility that the RAW will not be recoverable <grin>

 

If it all flashes, you forgot to replace the lens!!!

[DavidStone]

Nick asked:

 

 

Where do you still find the lightbulbs for the SEI???

 

I still have a spare bulb, so I've not started looking as yet, but most obsolete bulbs for most applications are still available, somewhere.

 

For those who wonder what on earth we're on about, The SEI meter is/was a photometer designed, I believe, for lighting engineers, and marketed by Ilford Ltd. scaled for photographic use. It uses the old 'grease-spot' principle of direct comparison of adjacent tones, with a one-degree spot. It will measure a luminance range of a million to one. Sufficient, probably, for the M8 and the best available RAW converter. I've not yet got beyond C1 LE, which came with the camera, so any advice in that direction is welcome.

 

David